Search for a command to run...
The results of most B3LYP and B3PW simulations, performed during the last quarter of century, dealing with ABO perovskite (001) surfaces, heterostructures, and oxygen vacancies therein, were reviewed. According to carried out B3LYP and B3PW simulations, almost all upper-layer atoms on the BO2- and AO-terminated STO, BTO, PTO, CTO, SZO, BZO, PZO, and CZO perovskite (001) surfaces shift inwards. Practically all ABO perovskite second-layer atoms shift upwards. Finally, nearly all third-layer atoms, once more, shift inwards. The ABO perovskite (001) surface energies, for both BO2 and AO terminations, are comparable. Computer simulations on the ABO perovskites indicate a significant rise of the B-O chemical bond covalency nearby the BO2-terminated (001) surfaces in comparison to their bulk. B3LYP- and B3PW-simulated ABO perovskite bulk Γ-Γ band gaps are decreased nearby their BO2- and AO-terminated (001) surfaces. We discuss recent B3PW simulations for the STO/BTO, STO/PTO, and SZO/PZO (001) heterostructures. Simulated optical band gaps of the STO/BTO, STO/PTO, and SZO/PZO (001) heterostructures mainly depend on the BO2- or AO-terminations of the upper layer of the augmented film. The displacement magnitudes of the nearest neighbor atoms, around the (001) surface oxygen vacancy, in the ABO perovskites, usually, are larger than in their bulk. In the STO, BTO, PTO, and SZO perovskites, the electronic charge, ordinarily, is a lot better localized inside the bulk than the (001) surface oxygen vacancy. In the STO, BTO, PTO, and SZO perovskites, the (001) surface oxygen vacancy-induced defect levels are located closer to the conduction band bottom than in the bulk cases. Simulated formation energy difference between the bulk and the (001) surface oxygen vacancies in the STO, BTO, PTO, and SZO perovskites triggers the oxygen vacancy segregation from the bulk towards the (001) surface. All computer simulations for ABO perovskites were performed in their high-symmetry cubic phase.